Field investigations on the vertical and horizontal distribution patterns of Bemisia tabaci (Gennadius) population on Bt cotton Guokang No. 22 and non-Bt cotton Simian No. 3 showed that in July, no obvious difference was found in the vertical distribution of B. tabaci population on cotton plant, but in August, the population density was significantly higher on the upper part of cotton plant than on its middle and lower parts. The horizontal distribution patterns of B. tabaci adult and nymph were similar. B. tabaci distributed evenly on cotton leaves when its population density was low, but aggregated when its population density was high. The greater the population density, the higher the aggregation rate was observed. Throughout the incidence stage, B. tabaci adult and nymph aggregated and diffused alternatively. No significant difference was observed in the spatial distribution pattern of B. tabaci on Bt and non-Bt cotton plants.